KR102255204B1 - Reconfigurable measuring device and method for controlling the device - Google Patents

Abstract

A reconfigurable measuring device and a method of controlling the device are disclosed. An apparatus according to an embodiment may include a modulator, an amplifier, and a demodulator, and may control the modulator and the demodulator according to a settable measurement mode. Here, the modulation unit and the demodulation unit may be composed of a chopper.

Description

Reconfigurable measuring device and method of controlling the device {RECONFIGURABLE MEASURING DEVICE AND METHOD FOR CONTROLLING THE DEVICE}

The following embodiments relate to an apparatus and method for measuring a physiological signal or an impedance signal.

Various medical devices are being developed for diagnosing a patient's health condition. Due to the convenience of the patient and the rapidity of the results of the medical examination in the medical examination process, the importance of medical equipment for measuring the electrical vital signs of the patient is emerging.

The biopotential is generated by an electric field formed in the body, and can be measured as a voltage at a specific site according to the strength of the electric field. The source of the biopotential is an excitable cell that exhibits electrical excitement in response to an electrical stimulus. Exciting cells induce an action potential according to electric excitation, and the action potential induced by the excitatory cells can be transmitted through nerve fibers. These action potentials can create an electric field within the body.

Also, like the biopotential signal, the impedance signal may be used to monitor the health or emotional state of the living body.

A reconfigurable measuring device according to one side comprises: a first chopper modulating an input signal; An amplifier amplifying the output signal of the first chopper; A second chopper demodulating the output signal of the amplifier; And a control unit for controlling the first chopper and the second chopper according to a settable measurement mode. Here, the measurement mode may include a biopotential measurement mode and an impedance measurement mode.

In this case, when the measurement mode is a biopotential measurement mode, the controller may provide a frequency signal corresponding to the biopotential measurement mode to the first chopper and the second chopper.

In addition, when the measurement mode is an impedance measurement mode, the controller may control the first chopper so that the input signal bypasses the first chopper. In addition, when the measurement mode is an impedance measurement mode, the controller may provide a frequency signal corresponding to the impedance measurement mode to the second chopper.

In addition, when the measurement mode is an impedance measurement mode, and a carrier frequency for impedance measurement is within a band of noise generated by the amplifier, the control unit generates a frequency signal corresponding to the biopotential measurement mode. It can be provided for 1 chopper and the second chopper.

In addition, the control unit may include a first mux (MUX) for selectively providing one of a first frequency signal and a constant voltage signal to the first chopper; And a second mux selectively providing any one of the first frequency signal and the second frequency signal to the second chopper. Here, the control unit may further include a phase shift unit for shifting the phase of the second frequency signal.

In addition, the reconfigurable measuring device further includes a first resistor unit for implementing a resistance component between a node between the first chopper and the amplifier and a node for a bias voltage using a capacitor and at least two switches, The control unit may activate the first resistance unit when the measurement mode is a bioelectric potential measurement mode.

In addition, the reconfigurable measuring device implements a resistance component between a first node between the first chopper and the amplifier and a node for a bias voltage using at least two resistors, and the first chopper and the amplifier Further comprising a second resistance unit for implementing a resistance component having the same resistance value as the resistance component between the second node between and the node for the bias voltage, the control unit when the measurement mode is the impedance measurement mode, the It is possible to activate the second resistance unit.

The reconfigurable measurement device according to the other side includes a plurality of measurement modules; And a controller for controlling the plurality of measurement modules so that each of the plurality of measurement modules selectively measures one of a biopotential and an impedance. Here, each of the plurality of measurement modules includes a modulator for modulating an input signal; An amplifier amplifying the output signal of the modulator; And a demodulator configured to demodulate the output signal of the amplifier.

A method of controlling a reconfigurable measurement device according to another aspect includes the steps of receiving a signal indicating a measurement mode; Providing a first signal to a first chopper according to the measurement mode; And providing a second signal to the second chopper according to the measurement mode. Here, the first chopper modulates the input signal using the first signal, and the second chopper demodulates the signal amplified by the amplifier using the second signal.

1 is a block diagram showing a reconfigurable measurement device according to an embodiment.
2 is a diagram illustrating an operation of a measuring device when measuring a biopotential signal according to an exemplary embodiment.
3 is a diagram for explaining an operation of a measuring device when impedance is measured according to an exemplary embodiment.
4 is a view for explaining a chopper according to an embodiment.
5 is a view for explaining a control unit according to an embodiment.
6 and 7 are block diagrams showing a measurement system using a reconfigurable measurement device according to an embodiment.
8A to 8D are circuit diagrams for explaining an input terminal of a measuring device according to an exemplary embodiment.
9 is a block diagram showing a measurement device including a plurality of reconfigurable measurement modules according to an embodiment.
10 is a flowchart illustrating a method of controlling a reconfigurable measuring device according to an exemplary embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a reconfigurable measuring device according to an embodiment. Referring to FIG. 1, a reconfigurable measuring device (hereinafter referred to as a'measuring device') 100 according to an embodiment includes an amplifier 120, a plurality of choppers 110 and 130, and a controller 140. Includes.

The measurement device 100 may operate in various measurement modes by controlling the first chopper 110 and the second chopper 130 using the control unit 140. For example, the measuring device 100 may measure a bio-potential.

The biopotential is generated by an electric field formed in the body, and can be measured as a voltage at a specific site according to the strength of the electric field. Bioelectric potentials include electrocardiogram (ECG, electrocardiogram), electromyogram (EMG), nerve conduction (ENG, electroneurogram), electroencephalogram (EEG), retinal conduction (ERG, electroretinogram), and safety (EOG, electrooculogram). . Electrocardiogram measurement is to measure the electrical activity of the heart by installing electrodes on the surface of the body, and electromyography is to measure contractile action by installing electrodes near the muscle, and nerve conduction measurement is to install electrodes near the peripheral nerves to measure the electrical activity of the heart. It is to measure the biopotential signal. Nerve conduction speed and delay time can be measured through nerve conduction measurement. EEG measurement is to measure the electrical activity of the brain by installing a surface electrode around the head, and the retinal conduction measurement is to measure the visual response phenomenon by installing an electrode on the inner surface of the retina or cornea. Safety measurement is to measure the movement state of the pupil by installing a surface electrode on the main surface of the eye.

The controller 140 may control the first chopper 110 and the second chopper 130 to measure the bioelectric potential. In order to measure the biopotential, a signal input through the electrode may be amplified by the amplifier 120. Here, the amplifier 120 may be a differential amplifier. The differential amplifier is an amplifier that amplifies the difference between two input signals, and may include, for example, an instrumentation amplifier (IA).

In this case, noise may be generated in the amplifier 120. For example, noise generated inside the amplifier 120 may be 1/f noise. 1/f noise is also referred to as flicker noise, and is inherent noise generated in an active device. When the noise generated inside the active element is displayed on the frequency axis, a shape in which the size of the noise increases significantly in a low frequency band (eg, 100 Hz or less) appears. In other words, the 1/f noise increases in inverse proportion to the frequency.

Since the biopotential signal is a low frequency signal, it may be interfered with due to noise generated by the amplifier 120. In order to prevent such interference, the controller 140 may control the first chopper 110 to modulate an input signal. For example, the controller 140 may control the first chopper 110 so that the input signal is modulated into a signal having a center frequency higher than the noise band. Accordingly, the amplifier 120 may amplify the modulated signal. Since the modulated signal has a center frequency outside the noise band, the signal amplified by the amplifier 120 may not be affected by noise. Also, the controller 140 may control the second chopper 130 to demodulate the amplified signal. For example, the controller 140 may control the second chopper 130 so that the amplified signal is demodulated into a signal having an original center frequency.

Alternatively, the measurement device 100 may measure impedance. Like the biopotential signal, the impedance signal can be used to monitor the health or emotional state of a living body. For example, the impedance representing the degree of resistance of the skin, the impedance representing the degree of skin hydration, the impedance that changes according to the breathing of the lungs, the impedance that changes according to the flow of blood, and the impedance that exists in the electrical path including the skin and the measuring electrode, etc. This can be measured.

The controller 140 may control the first chopper 110 and the second chopper 130 to operate in the impedance measurement mode. Unlike biopotential measurement, which measures a biopotential generated in the body, current generated outside the body may be used to measure impedance. For example, when the current generated by the current generator is provided to an impedance measurement portion, a voltage drop may occur due to the impedance of the impedance measurement portion. The measuring device 100 may measure the impedance by measuring a potential difference due to the voltage drop described above.

Bioelectrical impedance analysis is based on the law that the resistance of a uniform conductor of the same cross-sectional area of a certain length is proportional to the length and inversely proportional to the cross-sectional area. However, the human body is not a uniform cylindrical shape, and the conductivity in the human body is also not constant. In addition, the human body is composed of muscles that conduct electricity relatively well, and fat tissue that does not conduct electricity well with extracellular fluid. Therefore, various circuit models can be used to describe the electrical characteristics of the body. In particular, when an alternating current is passed through the body, electric charges may be charged to the cell membrane as the current passes through the cell membrane. In this case, the cell membrane serves as a capacitor, and electrical characteristics of the body can be modeled using the capacitor by the cell membrane. In addition, the degree of electrical transmission of the cell may vary according to the frequency of the alternating current. For example, since an alternating current of 5 kHz does not pass through the cell membrane, it can be used to measure extracellular fluid, and because an alternating current of 100 kHz or more passes through the cell membrane, it may be used to measure total body water (TBW).

When impedance is measured using an AC current, a signal input to the measuring device 100 may be a signal having a frequency of the AC current as a center frequency. The input signal can be used like a signal modulated using the frequency of an alternating current. The input signal may be amplified by the amplifier 120 for measurement.

As described above, noise may be generated in the amplifier 120. For example, 1/f noise may be generated inside the amplifier 120. Since the input signal has the frequency of the AC current as the center frequency, if the center frequency of the input signal is located outside the noise band generated by the amplifier 120, the input signal will not be interfered with the noise generated by the amplifier 120. I can. The controller 140 may control the first chopper 110 so that the input signal is bypassed as it is. For example, the controller 140 may provide a constant voltage signal of Vdd or GND to the first chopper 110.

The amplifier 120 may amplify the bypassed signal. Since the bypassed signal has a center frequency outside the noise band, the signal amplified by the amplifier 120 may not be affected by noise. Also, the controller 140 may control the second chopper 130 to demodulate the amplified signal. Since the amplified signal has a frequency of an AC current used for impedance measurement as a center frequency, the controller 140 may control the second chopper 130 to demodulate the amplified signal using the corresponding center frequency.

The reconfigurable measurement apparatus 100 according to an embodiment may be reconfigured into various measurement modes according to an application. Further, as will be described in detail below, the reconfigurable measurement apparatus 100 according to an embodiment may include a plurality of reconfigurable measurement modules. In this case, depending on the application, at least some measurement modules may operate in a biopotential measurement mode, and the remaining measurement modules may operate in an impedance measurement mode.

For example, since the shape of the electrical signal of the heart varies depending on the direction in the outer periphery surrounding the heart, the ECG may be measured using several channels. In this case, the measuring apparatus 100 may be reconfigured to measure an electrocardiogram in multiple channels, and to measure an interface impedance between an input terminal of a measuring circuit for measuring an electrocardiogram and a skin. When the electrocardiogram is measured in three channels, three measurement modules included in the measurement device 100 may be reconfigured to operate in a biopotential measurement mode. In addition, in order to measure the interface impedance in each channel, the other three measurement modules included in the measurement device 100 may be reconfigured to operate in the impedance measurement mode. In addition, since the real component and the imaginary component of the impedance signal can be measured according to the phase of the frequency provided to the second chopper 130 during impedance measurement, the other three measurement modules included in the measurement device 100 It can be reconfigured to operate in measurement mode.

Depending on the application, impedance measurement may not be required, or biopotential measurement using more channels may be required. The reconfigurable measuring apparatus 100 according to an embodiment may provide a technique capable of freely changing the configuration of biopotential measurement and impedance measurement according to an application.

2 is a diagram illustrating an operation of a measuring device when measuring a biopotential signal according to an exemplary embodiment. Referring to FIG. 2, the measuring apparatus 200 according to an embodiment includes a first chopper 210, an amplifier 220, and a second chopper 230. Although not shown in the drawing, the measuring apparatus 200 further includes a control unit, and the control unit may control the first chopper 210 and the second chopper 230.

Hereinafter, a mode in which an input signal is modulated, amplified, and demodulated while passing through the first chopper 210, the amplifier 220, and the second chopper 230 in the biopotential measurement mode will be described in detail. In each graph shown in FIG. 2, the x-axis represents frequency, and the y-axis represents power density. For example, an increase in the x-axis direction from the origin may mean that the center frequency of the electrical signal increases, and as the increase in the y-axis direction from the origin increases, it may mean that the intensity of the electrical signal increases.

The measuring device 200 may receive an input signal for measuring a biopotential through the input terminal 205. Hereinafter, an input signal for measuring a biopotential is referred to as a biopotential signal. Since the biopotential signal is a direct current signal or a low frequency signal, the biopotential signal in the graph corresponding to the input terminal 205 may be expressed as the signal 206. Since the biopotential signal generated in the human body does not have a strong power density, the biopotential signal may be amplified by the amplifier 220 in order to measure the biopotential signal. However, the amplifier 220 is an active element, and 1/f noise may be generated within the amplifier 220. In general, since the biopotential signal is located within the band of 1/f noise in the frequency domain, interference may occur due to 1/f noise when the biopotential signal is amplified as it is.

To prevent this, the controller may provide a signal having a higher frequency fc than the 1/f noise band to the first chopper 210. In this case, the biopotential signal in the graph corresponding to the node 215 between the first chopper 210 and the amplifier 220 may be expressed as the signal 216. The biopotential signal may be modulated into a signal 216 having a frequency fc as a center frequency while passing through the first chopper 210.

The signal 216 having the frequency fc as the center frequency may be amplified by the amplifier 220. In the graph corresponding to the inside of the amplifier 225, the biopotential signal may be expressed as the signal 226. As the biopotential signal passes through the amplifier 220, the power density increases. In addition, 1/f noise in the graph corresponding to the inside of the amplifier 225 may be expressed as the signal 227. 1/f noise can be noticeably generated in the low frequency band. In the graph corresponding to the inside of the amplifier 225, the signal 226 and the signal 227 do not overlap each other. This means that as the biopotential signal is modulated by the first chopper 210 to have the frequency fc as the center frequency, it is not interfered by 1/f noise.

The controller may control the second chopper 230 so that the amplified signal 226 is demodulated. For example, the controller may provide a signal having a frequency fc to the second chopper 230. In this case, the biopotential signal in the graph corresponding to the output terminal 235 may be expressed as the signal 236. The biopotential signal may be demodulated into a signal 236 having an original center frequency while passing through the second chopper 230. At the same time, a signal corresponding to 1/f noise may be modulated into a signal 237 having a frequency fc as a center frequency while passing through the second chopper 230. In the graph corresponding to the output terminal 235, the signal 236 and the signal 237 do not overlap each other. This means that as the biopotential signal is demodulated by the second chopper 230 and the 1/f noise is modulated by the second chopper 230, the biopotential signal is not interfered by the 1/f noise. .

In addition, the center frequency of the signal 236 of the graph corresponding to the output terminal 235 is the same as the center frequency of the signal 206 of the graph corresponding to the input terminal 205, and the signal of the graph corresponding to the output terminal 235 ( The power density of 236 is greater than the power density of the signal 206 of the graph corresponding to the input terminal 205. This means that the biopotential signal is not affected by 1/f noise when amplified or demodulated. In this way, the measuring apparatus 200 may provide a technique for controlling the first chopper 210 and the second chopper 230 so that the biopotential signal is amplified without being affected by 1/f noise.

3 is a diagram for explaining an operation of a measuring device when impedance is measured according to an exemplary embodiment. Referring to FIG. 3, the measuring apparatus 300 according to an embodiment includes a first chopper 310, an amplifier 320, and a second chopper 330. Although not shown in the drawing, the measuring device 300 further includes a control unit, and the control unit may control the first chopper 310 and the second chopper 330.

Hereinafter, a mode in which an input signal is bypassed, amplified, and demodulated while passing through the first chopper 310, the amplifier 320, and the second chopper 330 in the impedance measurement mode will be described in detail. In each graph shown in FIG. 3, the x-axis represents the frequency, and the y-axis represents the power density.

The measurement device 300 may receive an input signal for impedance measurement through the input terminal 305. Hereinafter, an input signal for impedance measurement is referred to as an impedance signal. The impedance signal includes information on a potential difference generated when the current generated by the current generator 340 flows to the human body 345 modeled as the impedance Z. Here, the current generator 340 may generate an AC current having a frequency fc.

Since the impedance signal has a frequency fc as a center frequency, the impedance signal in the graph corresponding to the input terminal 305 may be expressed as the signal 306. Since the current flowing to the human body 345 is very small, the power density of the impedance signal is not strong, and the impedance signal may be amplified by the amplifier 320 in order to measure the impedance signal.

Although 1/f noise may be generated in the amplifier 220, a frequency fc used to measure impedance is generally located outside a band of 1/f noise in the frequency domain. In this case, the impedance signal is not interfered with by 1/f noise, and the first chopper 310 does not need to modulate the impedance signal to prevent interference by 1/f noise. The controller may control the first chopper 310 so that the impedance signal bypasses the first chopper 310. For example, the controller may provide a constant voltage signal of Vdd or GND to the first chopper 310. When the impedance signal bypasses the first chopper 310, the impedance signals before and after passing through the first chopper 310 are substantially the same. In a graph corresponding to the node 315 between the first chopper 310 and the amplifier 320, the impedance signal may be expressed as a signal 306.

The impedance signal may be amplified by the amplifier 320. In the graph corresponding to the inside of the amplifier 325, the impedance signal may be expressed as the signal 326. As the impedance signal passes through the amplifier 320, the power density increases. In addition, 1/f noise in the graph corresponding to the inside of the amplifier 325 may be expressed as a signal 327. 1/f noise can be noticeably generated in the low frequency band. In the graph corresponding to the inside of the amplifier 325, the signal 326 and the signal 327 do not overlap each other. This means that since the impedance signal has a frequency fc as the center frequency, it is not interfered with by 1/f noise.

The controller may control the second chopper 330 so that the amplified signal 326 is demodulated. For example, the controller may provide a signal having a frequency fc to the second chopper 330. In this case, referring to the graph corresponding to the output terminal 335, the impedance signal may be demodulated into the signal 336 while passing through the second chopper 330. At the same time, a signal corresponding to 1/f noise may be modulated into a signal 337 having a frequency fc as a center frequency while passing through the second chopper 330. In the graph corresponding to the output terminal 335, the signal 336 and the signal 337 do not overlap each other. This means that as the impedance signal is demodulated by the second chopper 330 and the 1/f noise is modulated by the second chopper 330, the impedance signal is not interfered with by the 1/f noise. In this way, the measuring apparatus 300 may provide a technology for controlling the first chopper 310 and the second chopper 330 so that the impedance signal is amplified without being affected by 1/f noise.

4 is a diagram for describing a chopper according to an exemplary embodiment. Referring to FIG. 4, the chopper 400 according to an embodiment may connect input ports 450 and 460 to output ports 470 and 480 according to a control voltage (Vc). The chopper 400 may include a first switch 410, a second switch 420, a third switch 430, and a fourth switch 440 operating according to a control voltage.

The first switch 410, the second switch 420, the third switch 430, and the fourth switch 440 are turned on when the control voltage is logically '1', and the control voltage is logically '0'. If it is, these switches are turned off. In the drawing, the voltage Vcb controlling the third switch 430 and the fourth switch 440 is a voltage at which the control voltage Vc is logically inverted.

When the control voltage is logically '1', the first switch 410 and the second switch 420 are turned on, and the third switch 430 and the fourth switch 440 are turned off. In this case, the first input port 450 is connected to the first output port 470 and the second input port 460 is connected to the second output port 480. A state in which the first input port 450 and the first output port 470 are connected and the second input port 460 and the second output port 480 are connected may be referred to as a first state. In the first state, Vip = Vop and Vin = Von.

On the other hand, when the control voltage is logically '0', the first switch 410 and the second switch 420 are turned off, and the third switch 430 and the fourth switch 440 are turned on. In this case, the first input port 450 is connected to the second output port 480 and the second input port 460 is connected to the first output port 470. A state in which the first input port 450 and the second output port 480 are connected and the second input port 460 and the first output port 470 are connected may be referred to as a second state. In the second state, Vip = Von and Vin = Vop.

The controller 140 of FIG. 1 may provide an AC voltage or a DC voltage to the chopper 400 according to the measurement mode. When an AC voltage is provided to the control voltage Vc of the chopper 400, the chopper 400 may be switched between the first state and the second state for each period of the control voltage. For example, if the control voltage is an AC voltage of 1 kHz, the period of the control voltage is 1 ms. In this case, the chopper 400 includes both the first state and the second state every 1 ms. In other words, the chopper 400 may operate in the first state for 0.5 ms, may operate in the second state for the next 0.5 ms, and may operate in the first state for the next 0.5 ms.

When an AC voltage is provided to the chopper 400, the chopper 400 may modulate or demodulate an input signal based on the frequency of the AC voltage. For example, the chopper 400 switches a signal applied to the first input port 450 and a signal applied to the second input port 460 based on the period of the control voltage Vc to switch the first output port ( 470) and the second output port 480. In this case, the input signal may be modulated into a signal having the frequency of the control voltage Vc as the center frequency. Alternatively, when the input signal is a signal having the frequency of the control voltage Vc as the center frequency, the frequency component of the control voltage Vc included in the input signal may be removed by the chopper 400. In this case, the input signal may be demodulated into a signal that does not include the frequency component of the control voltage Vc.

When a DC voltage is provided to the control voltage Vc of the chopper 400, the chopper 400 may operate in either a first state or a second state according to a logical value of the DC voltage. For example, when the control voltage is Vdd, which is logically '1', the chopper 400 may operate in the first state. Alternatively, when the control voltage is GND, which is logically '0', the chopper 400 may operate in the second state.

When a DC voltage is provided to the chopper 400, the input signal may bypass the chopper 400. For example, the chopper 400 may maintain a first state or a second state according to the control voltage Vc. When the control voltage Vc is logically '1', since the chopper 400 maintains the first state, the input voltage may pass through the chopper 400 as it is. Alternatively, when the control voltage Vc is logically '0', since the chopper 400 maintains the second state, voltages applied to the input ports may be output in a switched form.

In the above, the embodiment of the chopper 400 implemented in a manner of controlling the flow of an electric signal according to the control voltage Vc has been described, but the configuration of the chopper 400 is not limited to the above-described embodiment. In some cases, the configuration of the chopper 400 may be variously modified. For example, the chopper 400 may further include a capacitor at each output terminal, and may be modified in a form in which an output value is determined according to an amount of charge stored in each capacitor.

5 is a diagram for describing a control unit according to an exemplary embodiment. Referring to FIG. 5, the measuring apparatus 500 according to an embodiment includes a first chopper 510, an amplifier 520, and a second chopper 520. The first chopper 510, the amplifier 520, and the second chopper 520, respectively, the matters described with reference to FIGS. 1 to 4 may be applied as it is.

The measuring device 500 includes a control unit 540, and the control unit 540 may be implemented using a MUX. For example, the controller 540 may include a first mux 541 for the first chopper 510 and a second mux 542 for the second chopper 530. The first mux 541 may provide a control voltage of the first chopper 510, and the second mux 542 may provide a control voltage of the second chopper 530.

The controller 540 may control the first mux 541 and the second mux 542 according to the measurement mode. For example, in the biopotential measurement mode, the control unit 540 includes the first mux 541 and the frequency signal for modulating or demodulating the biopotential signal to be provided to the first chopper 510 and the second chopper 530. The second mux 542 may be controlled. Alternatively, in the impedance measurement mode, the controller 540 may control the first mux 541 to provide a constant voltage signal for bypassing the impedance signal to the first chopper 510. The controller 540 may control the second mux 542 so that a frequency signal for demodulating the impedance signal is provided to the second chopper 530.

The first mux 541 may receive a frequency signal and a constant voltage signal for modulating a biopotential signal. For example, the first mux 541 may receive a frequency signal for modulating a biopotential signal as a first input signal, and may receive a constant voltage signal as a second input signal. The frequency signal for modulating the biopotential signal may be 4 kHz, and the constant voltage signal may be Vdd or GND.

The controller 540 may control the first mux 541 using the register REG_SEL_BP. The register REG_SEL_BP may be set to a value indicating a measurement mode. For example, when the register REG_SEL_BP is set to '1', the register REG_SEL_BP may indicate a biopotential measurement mode. When the register REG_SEL_BP is set to '0', the register REG_SEL_BP may indicate an impedance measurement mode. The controller 540 may provide the register REG_SEL_BP as a selection signal of the first mux 541.

When the register indicating the measurement mode (REG_SEL_BP) is logically '1', the first mux 541 may output a first input signal that is a frequency signal for modulating the biopotential signal. When the register indicating the measurement mode (REG_SEL_BP) is logically '0', the first mux 541 may output a second input signal that is a constant voltage signal for bypassing the impedance signal. The signal output by the first mux 541 is provided as a control voltage of the first chopper 510, and the operation of the first chopper 510 may be controlled by the control voltage.

The second mux 542 may receive a frequency signal for demodulating a biopotential and a frequency signal for demodulating an impedance signal. For example, the second mux 542 may receive a frequency signal for demodulating a biopotential signal as a first input signal, and may receive a frequency signal for demodulating an impedance signal as a second input signal. The frequency signal for demodulating the biopotential signal may be 4 kHz, and the frequency signal for demodulating the impedance signal may be 50 kHz.

The controller 540 may control the second mux 542 using a register (REG_SEL_BP) indicating the measurement mode. The controller 540 may provide the register REG_SEL_BP as a selection signal of the second mux 542. In some cases, the controller 540 may simultaneously control the first mux 541 and the second mux 542 using the same register REG_SEL_BP.

When the register indicating the measurement mode (REG_SEL_BP) is logically '1', the second mux 542 may output a first input signal that is a frequency signal for demodulating the biopotential. When the register indicating the measurement mode (REG_SEL_BP) is logically '0', the second mux 542 may output a second input signal that is a frequency signal for demodulating the impedance signal. The signal output by the second mux 542 is provided as a control voltage of the second chopper 530, and the operation of the second chopper 530 may be controlled by the control voltage.

The measuring device 500 may measure an impedance value of a real component and an impedance value of an imaginary component by adjusting a phase of a frequency signal for demodulating the impedance signal. For example, the measuring apparatus 500 may obtain an impedance value of a real component by demodulating the impedance signal using a frequency signal of phase 0°. In addition, the measuring apparatus 500 may obtain an impedance value of an imaginary component by demodulating the impedance signal using a frequency signal of a phase 90°.

To this end, the control unit 540 may further include a phase shifter 543. The phase shifter 543 may adjust a phase of a frequency signal for demodulating the impedance signal. For example, the phase shifter 543 may shift the phase of the frequency signal for demodulating the impedance signal by 90°. In this case, the phase-shifted frequency signal may be input as a second input of the second mux 542.

The controller 540 may control the phase shifter 543 using a register for phase shifting. The controller 540 may determine a size of a phase to be shifted based on a register value, and control the phase shifter 543 so that the phase is shifted by the determined size. For example, when the register for phase shifting is set to a value indicating phase 0°, the control unit 540 performs a phase shifter 543 so that a frequency signal for demodulating the impedance signal bypasses the phase shifter 543. ) Can be controlled. Alternatively, when the register for phase shifting is set to a value indicating a phase 90°, the controller 540 may control the phase shifter 543 so that the frequency signal for demodulating the impedance signal is phase shifted by 90°. have.

In the above, the embodiment in which the controller 540 includes the first mux 541, the second mux 542, and the phase shifter 543 has been described, but the configuration of the controller 540 may be variously modified. . For example, the measuring device 500 may include a first mux 541, a second mux 542, and a phase shifter 543 as separate components distinguished from the control unit 540. In this case, the controller 540 may generate a control signal for controlling the first mux 541, the second mux 542, and the phase shifter 543.

In addition, the controller 540 may generate a control signal that controls the current generator 550 for measuring impedance. For example, when the measurement mode is a biopotential measurement mode, the controller 540 may generate a control signal for deactivating the current generator 550. Alternatively, when the measurement mode is the impedance measurement mode, the controller 540 may generate a control signal for activating the current generator 550.

The controller 540 may control the current generator 550 using a register (REG_SEL_BP) indicating a measurement mode. For example, the controller 540 may provide a register (REG_SEL_BP) indicating a measurement mode to the current generator 550. The current generator 550 may be activated or deactivated according to the value of the register REG_SEL_BP indicating the measurement mode. When the value of the register REG_SEL_BP provided to the current generator 550 is '1', the measuring device 500 operates in a biopotential measurement mode, and thus the current generator 550 may be deactivated. On the other hand, when the value of the register (REG_SEL_BP) provided to the current generator 550 is '0', the measuring device 500 operates in the impedance measurement mode, so the current generator 550 generates a current for impedance measurement. Can be activated.

The current generator 550 may receive an AC signal having a frequency for impedance measurement. The current generator 550 may generate an AC current for impedance measurement by using an input AC signal. The AC signal may be input from the outside, and may be provided by the controller 540 in some cases.

According to another embodiment, the controller 540 may provide a frequency signal for modulating the impedance signal instead of providing a constant voltage signal to the first chopper 510 for impedance measurement. For example, when the frequency of the AC current for impedance measurement is included within the band of 1/f noise of the amplifier 520, the impedance signal may be interfered with by 1/f noise.

In order to prevent the impedance signal from being interfered with by 1/f noise, the controller 540 provides the first chopper 510 and the second chopper 530 with a frequency signal for modulating or demodulating the impedance signal. The 1 mux 541 and the second mux 542 can be controlled.

The first mux 541 may receive a frequency signal for modulating the impedance signal and a constant voltage signal for bypassing the impedance signal. For example, the first mux 541 may receive a frequency signal for modulating an impedance signal as a first input signal, and may receive a constant voltage signal as a second input signal. Here, the frequency signal for modulating the impedance signal may be the same as the frequency signal for modulating the biopotential signal described above.

The controller 540 may control the first mux 541 using the register REG_SEL_BP. As described above, when the register (REG_SEL_BP) is set to '1', the register (REG_SEL_BP) can indicate the biopotential measurement mode, and when the register (REG_SEL_BP) is set to '0', the register (REG_SEL_BP) May indicate the impedance measurement mode. However, when the frequency of the AC current for impedance measurement is included within the band of 1/f noise of the amplifier 520, the register REG_SEL_BP may be set to '1'. Accordingly, the first mux 541 and the second mux 542 may provide frequency signals for modulating and demodulating the impedance signal to the first chopper 510 and the second chopper 530.

Alternatively, when the frequency of the AC current for impedance measurement is included within the band of 1/f noise of the amplifier 520, the register (REG_SEL_BP) may be set to a separate '2' other than '0' or '1'. have. When '2' is received as a selection signal, the first mux 541 and the second mux 542 may output a frequency signal for modulating and demodulating the impedance signal. The output frequency signal may be provided to the first chopper 510 and the second chopper 530.

The operations of the control unit described above may be summarized as shown in Table 1.

Case Measurement mode First chopper (510) 2nd chopper (530) Case 1 Biopotential measurement fc_ECG fc_ECG Impedance measurement DC(Vdd or GND) fc_CG Case 2 Biopotential measurement fc_ECG fc_ECG Impedance measurement fc_ECG fc_ECG

Here, fc_ECG is a frequency for modulating or demodulating a biopotential signal, and fc_CG is a frequency of an AC current for impedance measurement.

Case 1 is a case in which the frequency (fc_CG) of the AC current for impedance measurement is higher than the 1/f noise band of the amplifier 520, for example, in Case 1, fc_CG = 50 kHz and fc_ECG = 4 kHz. In the biopotential measurement mode of Case 1, the controller 540 provides fc_ECG to both the first chopper 510 and the second chopper 530. In the impedance measurement mode of Case 1, the controller 540 provides DC to the first chopper 510 and fc_CG to the second chopper 530.

In addition, Case 2 is a case where the frequency (fc_CG) of the AC current for impedance measurement is within the 1/f noise band of the amplifier 520, for example, in Case 2, fc_CG = 50 Hz and fc_ECG = 4 kHz. In the biopotential measurement mode of Case 2, the controller 540 provides fc_ECG to both the first chopper 510 and the second chopper 530. In the impedance measurement mode of Case 2, the controller 540 provides fc_ECG to both the first chopper 510 and the second chopper 530.

In the impedance measurement mode of Case 2, the output signal of the second chopper 530 corresponds to a signal modulated with fc_CG. In general, in Case 2, since fc_CG is less than the sampling frequency of the analog-to-digital converter, the measurement device 500 performs analog-to-digital conversion of the signal modulated with fc_CG and then demodulates the fc_CG-modulated signal through digital signal processing. I can. Alternatively, the measurement device 500 may further include a third chopper that demodulates the output signal into fc_CG. In this case, the controller 540 may provide fc_CG to the third chopper in the impedance measurement mode of Case 2. Of course, the third chopper must be controlled so that the input signal is bypassed as it is in the other modes except for the impedance measurement mode of Case 2. To this end, the controller 540 may provide DC to the third chopper in modes other than the impedance measurement mode of Case 2.

6 and 7 are block diagrams illustrating a measurement system using a reconfigurable measurement device according to an embodiment.

Referring to FIG. 6, a measuring device 600 according to an embodiment includes a first chopper 610, an amplifier 620, a second chopper 630, a mux 640, and a current generator 650. . The first chopper 610, the amplifier 620, the second chopper 630, the mux 640, and each of the current generator 650 may be applied to the items described through FIGS. 1 to 5 as it is. Although not shown in the drawing, the measuring device 600 further includes a second mux for the second chopper 630, and provides a control signal for controlling the mux 640, the second mux, and the current generator according to the measurement mode. Can be generated.

The measurement device 600 may further include a high pass filter (HPF) 661. The high pass filter 661 is a filter that passes signals in a band above a predetermined frequency and blocks signals in a band below a predetermined frequency. The measuring device 600 may block a DC offset voltage using the high pass filter 661. As will be described in detail below, the amplifier 620 has an operating voltage range capable of amplifying an input signal at a desired ratio. When the DC offset voltage is included in the input voltage, the input voltage may exceed the operating voltage range of the amplifier 620. When the input voltage is out of the operating voltage range of the amplifier 620, the measurement device 600 may operate abnormally, such as saturation of the output voltage. The measuring device 600 may prevent abnormal operation of the measuring device 600 by using the high pass filter 661.

The measuring device 600 may further include a mutual conductance amplifying unit 662. The mutual conductance amplifier 662 may output a current proportional to the input voltage. For example, when the input voltage is high, a larger current can be output, and when the input voltage is low, a smaller current can be output. The amplifier 620 may be interlocked with the mutual conductance amplifying unit 662. The amplifier 620 may perform a mutual impedance amplification function. For example, the amplifier 620 may output a voltage proportional to the input current. As the current output by the mutual conductance amplifier 662 increases, the amplifier 620 outputs a larger voltage, and the smaller the current output by the mutual conductance amplifier 662, the amplifier 620 outputs a smaller voltage I can.

The measuring device 600 may further include a second amplifier 663. The second amplifier 663 is an amplifier with adjustable gain and may include, for example, a programmable gain amplifier (PGA). Using the second amplifier 663, the measuring device 600 may secondarily amplify the signal amplified by the amplifier 620. The range of an appropriate output signal may be different according to an application receiving the output signal of the measurement device 600. For example, the first application may receive 0V to 5V, while the second application may receive 0V to 20V. The measurement device 600 may control the gain of the second amplifier 663 so that an output signal is output within a voltage range suitable for an application.

The measurement device 600 may further include a low pass filter 664. The low pass filter 664 is a filter that passes signals in a band below a predetermined frequency and blocks signals in a band above a predetermined frequency. The measuring device 600 may remove high-frequency noise by using the low pass filter 664.

The measuring device 600 may further include a buffer 665. The buffer 665 may provide sufficient current to the analog-to-digital converter 666 in response to an input load of the analog-to-digital converter 666.

The measurement device 600 may further include an analog to digital converter (ADC) 666. The analog-to-digital converter 666 may convert an analog electrical signal into a digital electrical signal. The measuring device 600 may output a digital signal by converting the amplified analog signal into a digital signal using the analog-to-digital converter 666.

Referring to FIG. 7, a measuring apparatus 700 according to another exemplary embodiment includes a first chopper 710, an amplifier 720, a second chopper 730, and a current generator 750. The first chopper 710, the amplifier 720, the second chopper 730, and the current generator 750, respectively, the items described through FIGS. 1 to 5 may be applied as they are. Although not shown in the drawing, the measuring apparatus 700 further includes a controller, and the controller may control the first chopper 710, the second chopper 730, and the current generator 750 according to the measurement mode.

The measuring device 700 may further include a high pass filter 761. The measuring device 700 may block DC offset by using the high pass filter 761. The measuring apparatus 700 may prevent an abnormal operation of the amplifier 720 by blocking the DC offset using the high pass filter 761.

The measuring device 700 may further include a band pass filter 762. The band pass filter 762 is a filter that passes signals in a predetermined frequency band and blocks signals other than the predetermined frequency band. The measuring device 700 may remove high-frequency noise and low-frequency noise by using the band pass filter 762. In some cases, the band pass filter 762 may be replaced with a low pass filter. In this case, the measuring device 700 may remove high-frequency noise by using a low pass filter.

The measuring device 700 may further include a third chopper 740. Referring to Table 1, in the impedance measurement mode of Case 2, the controller provides the first chopper 710 and the second chopper 730 with a frequency signal for modulating and demodulating the impedance signal. In other words, the impedance signal is modulated with fc_ECG by the first chopper 710 and then amplified by the amplifier 720 and demodulated with fc_ECG by the second chopper 730. Since the impedance signal demodulated by the second chopper 730 is still a signal modulated with fc_CG, the control unit may provide fc_CG to the third chopper 740 so that the third chopper 740 demodulates it with fc_CG.

On the other hand, in other modes except for the impedance measurement mode of Case 2, the controller may provide DC to the third chopper 740. In this case, the third chopper 740 may bypass the input signal as it is.

The measurement device 700 may further include a second amplifier 763, a low pass filter 764, a buffer 765, and an analog-to-digital converter 766. The second amplifier 763, the low-pass filter 764, the buffer 765, and the analog-to-digital converter 766 may be applied as described in FIG. 6, and thus a more detailed description thereof will be omitted.

8A to 8D are circuit diagrams illustrating an input terminal of a measuring device according to an exemplary embodiment.

Referring to FIG. 8A, the measuring apparatus 800 according to an embodiment includes a first chopper 810, an amplifier 820, and a second chopper 830. Items described through FIGS. 1 to 7 may be applied to each of the first chopper 810, the amplifier 820, and the second chopper 830 as they are.

The measuring device 800 may further include a first capacitor unit 840, a first resistor unit 870, a second resistor unit 880, and a second capacitor unit 885. The first capacitor unit 840, the first resistor unit 870, the second resistor unit 880, and the second capacitor unit 885 implement a resistance component and a capacitor component constituting a high pass filter, and the amplifier ( A bias voltage may be provided to the input of 820. The high pass filter filters the DC offset voltage, and the bias voltage provided to the input of the amplifier 820 causes the amplifier 820 to operate within a normal operating range.

In the biopotential measurement mode, the first resistor unit 870 may be activated to provide a bias voltage to the input of the amplifier 820. In addition, in the biopotential measurement mode, a resistance component of the high pass filter may be implemented by a combination of the first chopper 810 and the second capacitor unit 885. The first capacitor unit 840 is composed of a capacitor component of a high pass filter.

In the impedance measurement mode, since the first chopper 810 is the same as the conductive line, the second capacitor unit 885 cannot be a resistance component. Accordingly, a resistance component of the high pass filter may be implemented by activating the second resistor unit 880. The first capacitor unit 840 is composed of a capacitor component of a high pass filter. In the impedance measurement mode, a bias voltage may be provided to the input of the amplifier 820 by the second resistor unit 880.

More details related to the operation of the first resistor unit 870 and the second resistor unit 880 will be described later with reference to FIGS. 8C and 8D, respectively.

The measuring device 800 may further include start circuits 850 and 860 for starting up the operation of circuits included in the measuring device 800. The amplifier 820 has a voltage range capable of amplifying an input signal at a desired ratio. Hereinafter, for convenience of description, a voltage range of the amplifier 820 capable of amplifying an input signal at a desired ratio is referred to as a normal operating range.

In order for the amplifier 820 to operate in a normal operating range in a transient state in which the measurement device 800 is turned off from a turn-on state, the start circuits 850 and 860 are provided with a predetermined reference voltage ( reference voltage) can be entered. For example, the initiation circuit 850 may provide a reference voltage as an input of the first chopper 810 for a short period of time. The initiation circuit 860 may provide a reference voltage as an input of the amplifier 820 for a short period of time. When the amplifier 820 is out of the unstable transient state, the initiation circuits 850 and 860 may be deactivated.

According to another embodiment, the initiation circuits 850 and 860 may be used to restore the amplifier 820. For example, when the input voltage sparks, the voltage component that rapidly rises is a high-frequency component, and thus may not be filtered by the high pass filter of the input terminal. The rapidly rising voltage component is input to the amplifier 820, and the amplifier 820 may be saturated while amplifying the rapidly rising voltage component. When the amplifier 820 is saturated, the amplifier 820 cannot amplify the input voltage above the saturated voltage. It can be understood that the input signal input to the amplifier 820 is out of the normal operating range due to the rapidly rising voltage component.

When the amplifier 820 is saturated, the initiating circuits 850 and 860 may input a predetermined reference voltage so that the amplifier 820 can operate in a normal operating range. In this respect, the initiation circuits 850 and 860 may be referred to as a recovery circuit.

The measuring device 800 may further include an input impedance improving circuit 890. The input impedance improving circuit 890 may improve an input impedance by feeding back a part of the output of the amplifier 820 to an input terminal.

Referring to FIG. 8B, each of the clock signals (clk_chp1, clk_chp2, clk_b1, clk_b2, clk_dem1, clk_dem2,) shown in FIG. 8A may be generated by a 2x1 mux. Each mux may be controlled by a register indicating a measurement mode (REG_ECG2IMP) and a register indicating which of the real and imaginary components of the impedance signal to be measured (REG_SEL_IMP_real).

Also, the control signal INIT for controlling the recovery circuits 850 and 860 may be generated by a processing unit that performs a saturation detection and fast recovery function. The processor may detect whether the amplifier 820 is saturated based on the outputs of the low pass filters (664 in FIG. 6 and 764 in FIG. 7) and generate a control signal INIT.

Referring to FIG. 8C, the first resistance unit 870 may be activated in the biopotential measurement mode. As will be described in detail below, since the second capacitor unit 885 can implement a resistance component together with the first chopper 810, the first capacitor unit 840, the first chopper 810, and the second capacitor unit ( 885) may constitute a high pass filter.

More specifically, the first resistor unit 870 may be disposed at a node between the first chopper 810 and the amplifier 820. Here, a node between the first chopper 810 and the amplifier 820 may include a first node and a second node. In some cases, the first node may be referred to as a positive node, and the second node may be referred to as a negative node. The amplifier 820 may be configured as a differential amplifier, and the voltage of the first node and the voltage of the second node may be provided as a first input and a second input of the differential amplifier, respectively.

The first resistor unit 870 may include a first switch 871, a second switch 872, and a first capacitor 873. The first switch 871, the second switch 872, and the first capacitor 873 may work together to apply a voltage value (bias) suitable for the input voltage of the amplifier 820 to the first node. . The bias voltage may have a preset voltage value, and may be GND in some cases. Resistance values implemented by the first switch 871, the second switch 872, and the first capacitor 873 may be much larger than a general resistance. Accordingly, the first resistor unit 870 may provide a bias voltage to the input of the amplifier 820 without substantially affecting the flow of current in the circuit.

The control signal clk_b1 of the first switch 871 is a clock signal having mutually exclusive values from the control signal clk_b2 of the second switch 872. For example, when the control signal (clk_b1) is logically '1', the control signal (clk_b2) is logically '0', and when the control signal (clk_b1) is logically '0', the control signal (clk_b2) is logically '1'. Is '1'. In other words, the first switch 871 and the second switch 872 may be alternately turned on.

The amount of charge flowing per unit time between the node for the bias voltage and the first node is determined according to the switching period of the control signal clk_b1 and the control signal clk_b2 and the capacitance of the first capacitor 873. The amount of charge flowing per unit time flowing between the node for the bias voltage and the first node corresponds to the magnitude of the current. In addition, the potential difference between the bias voltage and the voltage of the first node corresponds to the magnitude of the voltage. When the magnitude of the current and the magnitude of the voltage are determined, the magnitude of the resistor can be determined. In other words, a resistance component may be implemented between the node for the bias voltage and the first node according to the switching period of the control signal clk_b1 and the control signal clk_b2 and the capacitance of the first capacitor 873.

Likewise, the first resistor unit 870 may include a third switch 874, a fourth switch 875, and a second capacitor 876. The third switch 874, the fourth switch 875, and the second capacitor 876 may implement a resistance component for supplying an appropriate bias voltage to the second node. More specifically, a resistance component may be implemented between the node for the bias voltage and the second node according to the switching period of the control signal clk_b1 and the control signal clk_b2 and the capacitance of the second capacitor 876 .

The first chopper 810 acts as an equivalent resistance in combination with a capacitance formed at the input portion of the amplifier 820. Accordingly, the first chopper 810 may serve as a high pass filter together with the first capacitor unit 840. The capacitance formed at the input portion of the amplifier 820 is mainly the capacitance formed by the second capacitor portion 885 and the capacitance formed at the gate of the transistor (eg, MOSFET) at the input terminal of the amplifier 820. Do. Here, by adjusting the capacitance value of the capacitor C_HPF_cutp included in the second capacitor unit 885 and the capacitance value of the capacitor C_HPF_cutn, the cut-off frequency of the input high pass filter HPF can be adjusted. have. For example, the cut-off frequency of the input high pass filter may be adjusted to 0.5 Hz and 10 Hz.

In the impedance measurement mode, while the first switch 871 and the third switch 874 are turned off, the first resistor unit 870 may be deactivated.

Referring to FIG. 8D, the second resistor unit 880 may be activated in the impedance measurement mode. As will be described in detail below, since the second resistor unit 880 may implement a resistance component, a high pass filter may be configured by a combination of the second resistor unit 880 and the capacitor unit 840.

More specifically, the second resistor unit 880 may include a switch 881, a chopper 882, a first resistor 883, and a second resistor 884. The switch 881 may activate or deactivate the second resistor unit 880. As the switch 881 is turned on in the impedance measurement mode, the second resistor unit 880 may be activated. In the biopotential measurement mode, the second resistor unit 880 may be deactivated while the switch 881 is turned off.

The reason why the resistance component, which is a component of the high pass filter, is implemented differently in the biopotential measurement mode and the impedance measurement mode is as follows. In the biopotential measurement mode, since the first chopper 810 is driven, capacitances of the input terminal of the amplifier 820 and the action of the first chopper 810 may be combined to serve as an equivalent resistance. Accordingly, in the biopotential measurement mode, a high pass filter is formed by a combination of capacitances of the first chopper 810 and the input terminal of the amplifier 820. On the other hand, in the impedance measurement mode, since the first chopper 810 serves only as a bypass, the capacitances of the input terminal of the amplifier 820 cannot act as equivalent resistance. For this reason, separate resistors 883 and 884 are required in the impedance measurement mode.

In the biopotential measurement mode, since the measurement band is a low frequency, the cut-off frequency of the high pass filter can be set to 0.5 Hz. In the impedance measurement mode, since the input signal is modulated according to the carrier frequency of the current applied to the current generator 750 of FIG. 7, the cut-off frequency of the input high pass filter may be related to the carrier frequency. For example, when the frequency of the current applied from the current generator 750 is 50 kHz, the cut-off frequency of the input high pass filter in the impedance measurement mode may be set to 5 kHz.

The chopper 882, the first resistor 883, and the second resistor 884 are implemented between the first node and the node for the bias voltage and the second node and the node for the bias voltage. The resistance can be made substantially the same. Since the first resistor 883 and the second resistor 884 physically use different resistors, the resistance value of the first resistor 883 and the resistance value of the second resistor 884 are substantially different due to an error in the manufacturing process. May not be the same. The chopper 882 may receive the clock signals clk_avg1 and clk_avg2, and may switch a path inside the chopper 882 for each period of the clock signal. In this case, even if the first resistor 883 and the second resistor 884 differ with a slight error, the average of the first resistor 883 and the second resistor 884 at the first node and the second node in time average The effect of applying the resistance value can be obtained.

9 is a block diagram illustrating a measurement device including a plurality of reconfigurable measurement modules according to an exemplary embodiment. Referring to FIG. 9, a measuring device 900 according to an exemplary embodiment includes a plurality of measuring modules 910 and 920.

The measurement device 900 may control each of the plurality of measurement modules 910 and 920 according to a measurement mode of each of the plurality of measurement modules 910 and 920. For example, when the first measurement module 910 is in the biopotential measurement mode, the control unit 930 included in the measurement device 900 is used for measuring biopotential by choppers included in the first measurement module 910. Control signals can be provided. Alternatively, when the second measurement module 920 is in the impedance measurement mode, the controller 930 may provide control signals for impedance measurement to choppers included in the second measurement module 920.

Since the items described above through FIGS. 1 to 8 may be applied to each of the plurality of measurement modules 910 and 920 as they are, a more detailed description will be omitted.

10 is a flowchart illustrating a method of controlling a reconfigurable measuring device according to an exemplary embodiment. Referring to FIG. 10, a method of controlling a measurement device according to an embodiment includes receiving a signal indicating a measurement mode (1010), providing a first signal to a first chopper (1020), and a second method. And providing 1030 a second signal to the chopper.

Each of the steps included in the method of controlling the measuring device may be performed by a controller included in the measuring device. For example, in step 1010 of receiving a signal indicating a measurement mode, the controller may read a register value recorded in a register indicating the measurement mode. Each of the steps illustrated in FIG. 10 may be applied as described above through FIGS. 1 to 8, and thus a more detailed description thereof will be omitted.

The apparatus described above may be implemented as a hardware component, a software component, and/or a combination of a hardware component and a software component. For example, the devices and components described in the embodiments are, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA). , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions, such as one or more general purpose computers or special purpose computers. The processing device may execute an operating system (OS) and one or more software applications executed on the operating system. Further, the processing device may access, store, manipulate, process, and generate data in response to the execution of software. For the convenience of understanding, although it is sometimes described that one processing device is used, one of ordinary skill in the art, the processing device is a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that it may include. For example, the processing device may include a plurality of processors or one processor and one controller. In addition, other processing configurations are possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of these, configuring the processing unit to behave as desired or processed independently or collectively. You can command the device. Software and/or data may be interpreted by a processing device or, to provide instructions or data to a processing device, of any type of machine, component, physical device, virtual equipment, computer storage medium or device. , Or may be permanently or temporarily embodyed in a transmitted signal wave. The software may be distributed over networked computer systems and stored or executed in a distributed manner. Software and data may be stored on one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -A hardware device specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operation of the embodiment, and vice versa.

Although the embodiments have been described by the limited embodiments and drawings as described above, various modifications and variations can be made from the above description to those of ordinary skill in the art. For example, the described techniques are performed in a different order from the described method, and/or components such as systems, structures, devices, circuits, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and those equivalent to the claims also fall within the scope of the claims to be described later.

Claims (29)

A first chopper modulating the input signal;
An amplifier amplifying the output signal of the first chopper;
A second chopper demodulating the output signal of the amplifier; And
A control unit that controls the first chopper and the second chopper according to a settable measurement mode
Including,
When the measurement mode is an impedance measurement mode, the controller controls the first chopper so that the input signal bypasses the first chopper.
The method of claim 1,
The measurement mode is a reconfigurable measurement device including a biopotential measurement mode and an impedance measurement mode.
The method of claim 1,
When the measurement mode is a biopotential measurement mode, the control unit provides a frequency signal corresponding to the biopotential measurement mode to the first chopper and the second chopper.
delete The method of claim 1,
When the measurement mode is an impedance measurement mode, the controller provides a frequency signal corresponding to the impedance measurement mode to the second chopper.
The method of claim 1,
When the measurement mode is an impedance measurement mode and a carrier frequency for impedance measurement is within a band of noise generated by the amplifier, the controller transmits a frequency signal corresponding to the biopotential measurement mode to the first chopper. And a reconfigurable measuring device provided to the second chopper.
The method of claim 6,
An analog-to-digital converter for analog-to-digital conversion of the output signal of the second chopper; And
A demodulator for demodulating the converted digital signal based on the carrier frequency
Reconfigurable measurement device further comprising a.
The method of claim 6,
A third chopper that demodulates the output signal of the second chopper using the carrier frequency
Reconfigurable measurement device further comprising a.
The method of claim 8,
When the measurement mode is a biopotential measurement mode, the controller controls the third chopper so that the output signal of the second chopper bypasses the third chopper.
The method of claim 1,
The control unit
A first mux (MUX) selectively providing one of a first frequency signal and a constant voltage signal to the first chopper; And
A second mux selectively providing any one of the first frequency signal and the second frequency signal to the second chopper
Reconfigurable measurement device comprising a.
The method of claim 10,
The control unit
A phase shift unit for shifting the phase of the second frequency signal
Reconfigurable measurement device further comprising a.
The method of claim 10,
Current generation unit for generating a current for impedance measurement based on the second frequency signal
Including more,
The control unit is a reconfigurable measurement device that activates the current generation unit when the measurement mode is an impedance measurement mode.
The method of claim 1,
A first resistor unit implementing a resistance component between a node between the first chopper and the amplifier and a node for a bias voltage using a capacitor and at least two switches
Including more,
The control unit is a reconfigurable measurement device that activates the first resistance unit when the measurement mode is a biopotential measurement mode.
The method of claim 1,
Using at least two resistors, a resistance component is implemented between a first node between the first chopper and the amplifier and a node for a bias voltage, and a second node between the first chopper and the amplifier and the bi A second resistor unit that implements a resistance component having a resistance value equal to the resistance component between nodes for an earth voltage
Including more,
The control unit is a reconfigurable measurement device that activates the second resistance unit when the measurement mode is an impedance measurement mode.
The method of claim 1,
Recovery unit providing a voltage corresponding to the normal operation region of the amplifier as an input of the amplifier
Reconfigurable measurement device further comprising a.
A plurality of measurement modules; And
A control unit for controlling the plurality of measurement modules so that each of the plurality of measurement modules selectively measures one of a biopotential and an impedance
Including,
Each of the plurality of measurement modules
A modulator for modulating an input signal;
An amplifier amplifying the output signal of the modulator; And
A demodulator that demodulates the output signal of the amplifier
Including,
The control unit provides a constant voltage signal to a modulator included in a measurement module for measuring impedance, and provides a second frequency signal to a demodulation unit included in the measurement module,
The modulator included in the measurement module is a reconfigurable measurement device that bypasses the input signal of the measurement module.
The method of claim 16,
The control unit provides a first frequency signal to a modulator included in a measurement module for measuring a living body potential, and provides the first frequency signal to a demodulation unit included in the measurement module.
The method of claim 17,
The first frequency signal is a reconfigurable measurement device having a frequency higher than a band of noise generated by an amplifier included in the measurement module.
The method of claim 16,
The control unit provides a constant voltage signal to a modulator included in a measurement module for measuring impedance, and provides a second frequency signal to a demodulator included in the measurement module.
The method of claim 19,
The modulator included in the measurement module is a reconfigurable measurement device that bypasses the input signal of the measurement module.
The method of claim 16,
The second frequency signal is a reconfigurable measuring device having the same frequency as a carrier frequency for impedance measurement.
The method of claim 16,
When the carrier frequency for impedance measurement is within the band of noise generated by the amplifier included in the measuring module for measuring impedance, the control unit includes a first frequency signal having a frequency higher than the band of noise in the measurement module A reconfigurable measurement device provided to the modulator and demodulator.
Receiving a signal indicating a measurement mode;
Providing a first signal to a first chopper according to the measurement mode; And
Providing a second signal to a second chopper according to the measurement mode
Including,
The first chopper modulates an input signal using the first signal, and the second chopper demodulates the signal amplified by an amplifier using the second signal,
When the measurement mode is an impedance measurement mode, the first signal includes a constant voltage signal, and the first chopper bypasses the input signal.
The method of claim 23,
The measurement mode comprises a biopotential measurement mode and an impedance measurement mode.
The method of claim 23,
When the measurement mode is a biopotential measurement mode, the first signal and the second signal include the same frequency signal corresponding to the biopotential measurement mode.
delete The method of claim 23,
When the measurement mode is an impedance measurement mode, the second signal includes a frequency signal corresponding to the impedance measurement mode.
The method of claim 23,
When the measurement mode is an impedance measurement mode and a carrier frequency for impedance measurement is within a band of noise generated by the amplifier, the first signal and the second signal correspond to the biopotential measurement mode. A method of controlling a reconfigurable measurement device comprising the same frequency signal.
A computer-readable recording medium on which a program for executing the method of any one of claims 23 to 25 and 27 to 28 is recorded.

Images